A wind turbine generator set utilizes natural wind energy to drive blades and a generator main shaft to rotate so as to drive a motor rotor to rotate and to generate electric power, thereby having the characteristics of environmental friendliness and the like, and being widely used.
At present, a majority of wind turbine generator sets are in a three-blade drive form with a main shaft horizontally arranged; a fan of the structure increases rated output power by increasing a length of each blade, i.e. increasing a wind-swept area of each blade, so that while the power of the fan is increased an overall size and a height of the fan are also increased, a relatively high fan body and relatively long blades increase a vibration degree of the whole fan and a fracture probability of the blades, resulting in reduction of wind resistance and great increasing of design requirements for the structure, strength and materials of the whole fan; particularly the asynchronous adjustment for an angle of each blade increases the production, operation and daily maintenance cost; a smaller available range of a wind speed (when the wind speed is greater than 25 m/s, stopping is generally adopted to avoid the danger) leads to the waste of a great amount of wind power resources and increasing cost of the electric energy per unit kilowatt; and generally the fan has the problems of large investment on wind power equipment, long cost recovery period and less annual utilization hours. The civil fan is limited to the cost and structure, so that the angle of the blades is non-adjustable, and the overspeed “flying” failure of a wind wheel is common. In addition, the blades of the fan of the structure are limited to the materials and structure, so that the probability of bulging, fracturing and breaking of the blades struck by lightning is relatively high.
In addition, a horizontal-axis wind turbine with door-shaped blades and a retractable wind wheel disclosed in a Chinese patent with the patent number of ZL 201420077847.5 and a horizontal-axis wind turbine with paddle-shaped blades and a drum-type retractable wind wheel disclosed in a Chinese patent with the patent number of ZL 201420078001.3 solve partial problems for synchronizing the blades, reducing the size of the fan and the like; however, since the wind wheel structure is formed by two to three circular frames and a plurality of supporting rods, the weight of a whole fan head portion is not reduced; moreover, an adjusting mechanism of the blades adopt a way of forming a groove on the frame and pulling by virtue of a steel cable, so that the structure is complicated, and the corrosion resistance, the daily maintenance and the repairing are relatively difficult; and moreover, a frictional loss of the steel cable and the frame groove is relatively large, resulting in undesirable overall operation and unit power generation cost.